Re: [RFC] net/bridge: port based vlan filtering for bridges

Benjamin LaHaise
2012-04-11T15:36:30Z

On Wed, Apr 11, 2012 at 08:30:52AM -0700, Stephen Hemminger wrote:
> On Wed, 11 Apr 2012 11:10:02 -0400
> Benjamin LaHaise <bcrl@kvack.org> wrote:
>
> > Hello folks,
> >
> > Attached is the first stab at a patch to make it possible to filter packets
> > received from other bridge ports based on the port number. This can be used
> > to emulate port based VLANs that some switches support.
> >
> > The justification for this is a bit interesting. Initially, I had been
> > filtering packets using firewall rules. Unfortunately, the number of
> > filter rules becomes impossible to manage when trying to filter traffic
> > between 100 different ports. CPU overhead of the filters is also a major
> > problem.
> >
> > The particular use-case I'm dealing with is simulating wireless networks
> > on a system using LXC containers. Each guest has a veth device that is a
> > member of the bridge, but the topology of which nodes can "hear" each other
> > changes at runtime.
> >
> > Comments/thoughts?
> >
>
> Nak. If firewall doesn't work then implement a better netfilter
> module.

That still results in the CPU overhead of packet duplication for each and
every bridge port regardless of the port receiving the packet or not.
Hmmmm, would a NF_HOOK in should_deliver be okay?

-ben
--
"Thought is the essence of where you are now."